Spin Crossover in Nitrito‐Myoglobin as Revealed by Resonance Raman Spectroscopy. Issue 34 (15th July 2016)

• Record Type: Journal Article
• Authors: Lambrou, Alexandra; Ioannou, Androulla; Pinakoulaki, Eftychia
• Is Part Of: Chemistry. Volume 22:Issue 34(2016)
• Page Start: 12176
• Page End: 12180
• Publication Date: 2016-07-15
• Subjects: heme proteins -- nitrite ligands -- Raman spectroscopy -- spin crossover; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201601738
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The myoglobin (Mb) heme Fe‐O‐N=O and heme Fe‐O‐N=O/2‐nitrovinyl species have been characterized by resonance Raman spectroscopy. In the heme Fe‐O‐N=O species, the bound nitrite ligand is removed by solvent exchange, thus reforming metmyoglobin (metMb). The high‐spin heme Fe‐O‐N=O unit is converted into a low‐spin heme Fe‐O‐N=O/2‐nitrovinyl species that can be reversibly switched between a low‐ and a high‐spin state without removing the bound nitrite ligand, as observed in the case of the heme Fe‐O‐N=O species. This spin‐state change is likely to be accompanied by a general structural rearrangement in the protein‐binding pocket. This example is the first of a globin protein that can reversibly change its metal spin state through an internal perturbation. These findings provide a basis for understanding the structure–function relationship of the spin cross found in other metalloenzymes and Fe III –porphyrin complexes. Abstract : Switching over : The heme Fe‐O‐N=O/ 2‐nitrovinyl myoglobin species can be reversibly switched between low‐ and high‐spin states (see figure; NMb=nitri‐myoglobin). This spin‐state change is likely to be accompanied by a general structural rearrangement in the protein‐binding pocket. This example is the first of a globin protein that can reversibly change its metal spin state through an internal perturbation.